40 lines
1.2 KiB
Python
40 lines
1.2 KiB
Python
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"""Convert times to and from HTTP-date serialisations.
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Reference: https://www.rfc-editor.org/rfc/rfc7231#section-7.1.1.1
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"""
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import time
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import warnings
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from email.utils import formatdate, parsedate_tz
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from sphinx.deprecation import RemovedInSphinx90Warning
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_GMT_OFFSET = float(time.localtime().tm_gmtoff)
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def epoch_to_rfc1123(epoch: float) -> str:
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"""Return HTTP-date string from epoch offset."""
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return formatdate(epoch, usegmt=True)
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def rfc1123_to_epoch(rfc1123: str) -> float:
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"""Return epoch offset from HTTP-date string."""
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t = parsedate_tz(rfc1123)
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if t is None:
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raise ValueError
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if not rfc1123.endswith(" GMT"):
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warnings.warn(
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"HTTP-date string does not meet RFC 7231 requirements "
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f"(must end with 'GMT'): {rfc1123!r}",
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RemovedInSphinx90Warning, stacklevel=3,
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)
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epoch_secs = time.mktime(time.struct_time(t[:9])) + _GMT_OFFSET
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if (gmt_offset := t[9]) != 0:
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warnings.warn(
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"HTTP-date string does not meet RFC 7231 requirements "
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f"(must be GMT time): {rfc1123!r}",
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RemovedInSphinx90Warning, stacklevel=3,
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)
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return epoch_secs - (gmt_offset or 0)
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return epoch_secs
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